I. Field of the Invention
The present invention relates to a method to detect bacteria, the method comprising the following steps: coupling bacteriophages and/or bacteriophage proteins to a support, incubating the support coupled to the bacteriophages and/or bacteriophage proteins with a sample, optionally removing the sample and the bacteria in the sample not bound to the bacteriophages and/or bacteriophage proteins, optionally adding substances permeabilizing or destroying the bacterial membrane, and detecting the bacteria of the sample bound to the bacteriophages and/or bacteriophage proteins, wherein the bound bacteria are not subjected to any cultivation step.
II. Related Art
The rapid and exact detection of bacteria is the first essential step for the diagnosis and treatment of a bacterial infection in human and animals as well as to initiate preventive measures. Furthermore, the detection is useful to control hygienic and quality of raw materials and processed foodstuff and for the control of hygienic and quality of fresh water and washing water and of water quality of public pools. Additionally, the detection is useful for process monitoring and optimization and for quality control in environmental analytics. Quite in contrast to most of the previously applied procedures, the method described herein also allows a simple detection at the place of need.
The detection of bacteria in biological samples in most cases occurs by means of a combination of cultivating methods by monitoring metabolic activities. For the purpose of phage-typing of bacterial strains of one type of bacteria cultivating methods having a sensitivity for bacteria are coupled to typing bacteriophages. This method involves a dense bacterial lawn on an agar plate of the sample to be analyzed which is overlaid with a suspension of bacteriophages in soft agar, said bacterial lawn having been obtained by isolating a single colony, and subsequent multiplication of said colony. The result is obtained after incubation overnight at the optimum bacterial growth temperature, which usually is 37° C. in most cases, by counting the plaques and by the control of the plaque morphology. A typing variant considers the measurement of adenylate kinase subsequent to phage-mediated cell lysis. In this method, an overnight culture of the bacteria to be analyzed is diluted in buffer, phages are added to it, and lysis is measured by means of specific phages per adenylate kinase activity.
In all methods described thus far, detection does not occur prior to lysis, or detection occurs via lysis. This allows monitoring of sources of infection and detection of sources of infection. This typing has been established for years in regard of numerous bacteria such as Salmonella typhi, Salmonella paratyphi B, Staphylococcus aureus, Pseudomonas aeruginosa as well as a number of further bacteria. These established detection methods yield a result only after several days in most cases. However, on the other hand, it is the rapid and exact determination of the type of bacteria (typing) that is of great importance for a rapid reaction.
Recently, more rapid molecular biological detection methods such as the polymerase chain reaction have been employed, which methods have the drawback, however, that they are more prone to contaminations. Likewise, with these methods the result is regularly available only after one day.
Furthermore, identification of the bacterial genus in some cases even requires the submission of samples to highly specialized reference laboratories, likewise resulting in a time and cost intensive factor.